Method of building up metal parts



Patented July 18, 1939 UNITED STATES PATENT OFFICE METHOD OF BUILDING UPMETAL PARTS No Drawing. Application July 16, 1935, Serial No. 31,621

7 Claims.

process effective progressively to melt the end- IBportion-s of the rodand bond the molten metal to the part, and, after the part is graduallybuilt up in this way and cooled, to machine it to the desired shape andsize.

In the attempt to condition metal parts in this way it has been foundthat known metals suitable for welding are diflicult to machine,especially after being subjected to the welding operation for buildingup the part. Further, it has been found that weld metals heretofore pro-25 posed have the defect of presenting poor bearing metals due to thetendency of the bearing made of them to seize or grab as it is commonlytermed.

Applicant has found, that by suitably incorporating uncombined lead intothe metal of which thepart is built up, the, same may be readilymachined, although such metal containing lead it has been found would beunsuitable for ordinary welding -purposes because lead would act a toweaken the strength of the welded joint uniting the parts weldedtogether. Further, the uncombined lead it has been found acts to preventsocalled seizing or grabbing in the bearing, probably because its actionis in the nature' 40 of a lubricant.

In the practice of the invention, the base metal of which the part isbuilt up is such that it will not alloy with lead, in order that thelead may.

For convenience (Cl. 2l910) in this sense with lead, or with lead alloywhich is in effect lead, is referred to in the appended claims as leadedcupreous metal. Satisfactory results will ordinarily be secured withappreciable amounts of lead up to about 5 or 6%, although for some usesthe amount of lead may be advantageously increased up to about Thewelding metal, which conveniently may be in the shape of a rod, may bemade by introducing lead into the melt and easing the rod, or aftercasting the billet cold rolling it to the desired size and shape to formthe rod. In such rods the lead will be only mechanically associated withthe copper or copper alloy for the reason that it will exist only as amechanical mixture therewith, the lead being dispersed throughout therod in the form of minute globules. However, working copper or copperalloys containing lead is ordinarily an expensive process because leadordinarily renders such metal hot short, that is to say, such metalscannot be hot rolled or otherwise worked hot.

Conveniently, therefore, the welding rod consists of copper or acopper-base alloy which can be hot worked and has the lead mechanicallyassociated with it in some way other than by introducing the lead intothe melt of which the rod material is formed. Preferably this is done byhot rolling a lead-free copper or copper-base alloy into rods, or it maybe done by hot rolling the metal into sheets, say about thick, andshearing the sheets to form rods of approximately square cross-section,the opposite sides being left rough as the result of the shearingoperations. The rod, however formed, may be coated with lead by dippingit into molten metal or spraying it with it, the roughened surfaces ofthe rod when sheared causing a greater amount of lead to adhere thanwould otherwise be the case. For a rod of given weight, a square orother polygonal cross-section of the rod it will be understood providesa greater surface area for adherence of the lead than would otherwise bethe case if the rod were circular in crosssection.

It will be understood that the lead may be mechanically associated withthe copper or cop- 'per-base alloy in other ways as, for example, byemploying tubing with a lead filler, or by wrapping the rod with leadtape, or by drawing or extruding a lead tube over the rod, or byelectro-depositing a coating of lead upon the rod, or by any of theknown methods of forming composite rods.

It is also possible to coat the rod with lead dust, or other forms ofcomminuted lead, mixed with a binder to make the lead adhere to the rod.Such a coating may be formed by mixing lead dust with a suiiicientamount of sodium or potassium silicate and water, say two-thirdspotassium silicate and one-third water, to form a paste of theconsistency of a rather thick paint, which paste may be applied to therod by dipping it into the paste, or by use of a brush.

It is also possible to coat a copper rod, or one formed of acopper-content alloy, with separate layers of lead and tin, or with alead-tin or other lead-content alloy, and upon melting of the rod thetin, or other non-lead constituents soluble in copper, will dissolve inthe copper or copperbase while the lead will be distributed through themass as a mechanical mixture with it. It is possible, when both tin andlead are present in the rod, either in the form of separate metals or asan alloy, the dispersed lead in the weld metal may contain a little tinin amount determined by the relative solubility of tin in lead andcopper. However, so far as effective results have been observed, thisdoes not reduce the efiicacy of the dispersed lead. It will therefore beunderstood that a lead-tin, or other alloy of lead and a constituenthighly soluble in copper, will be materially if not wholly reduced towhat in effect amounts to free lead. It will be understood that theamounts of lead and tin employed in these examples will be such as toincorporate into the metal deposited on the metal part the percentagesof lead and tin herein else where specified, and that in this wayadditional lead and tin may be added to the alloy or mixture of whichthe body of the rod is formed when said alloy or mixture alreadycontains these metals.

The rod also may be coated or otherwise me-,

chanically associated with a lead compound and a reducing agent to formmetallic lead during the welding operation. This lead compound mayconsist of lead oxide or red lead, and the reducing agent may consist oflamp black or other carbonaceous substance. The lead compound and thelamp black may be mixed with a suitable binder to form a paste which maybe applied to therod by a brushing or dipping operation. For example, 10parts lead oxide may be mixed with 1 part lamp black and a mixture ofpotassium or sodium silicate and water, say two-thirds potassiumsilicate to one-third water, to form a paste. As a substitute for lampblack, colloidal graphite may be employed. As binders liquid shellac andlinseed oil may be employed, which carbonaceous substances will producea char that also will act as a reducing agent. Conveniently the leadoxide or other lead compound of which the paste is formed is in a finelydivided state as, for example, a powder which will pass through an to200 mesh screen, sufficient of a binder being employed to form a ratherthick paint.

The operation of building up the metal part by use .\of the abovedescribed welding rods is performed by depositing the rod thereon by useof an electric arc. Preferably the operation is performed byarc-depositing the material of the rod by use of the so-called carbon"arc" process, although, if desired, it may be performed by use of the.so-called electric metallic arc process. Applicant has found that animproved dispersion of the lead may be secured by the use of theseprocesses, all of them securing a much better dispersion of the leadthan can be obtained by a casting process. During the welding proceses asmall amount of lead is melted with the copper or copper alloy fractionsof the rod being deposited and is dispersed and uniformly mixed withthem to form the weld metal. For example, in depositing a lead-coatedcopper alloy rod by the arc process, the copper alloy at the end of therod is gradually and progressively melted, the lead adjacent the end ofthe rod gradually melting with it and flowing into the are, which latterfinely disperses the lead and uniformly mixes it with the copper a1-'1oy as the latter is deposited. Further it has Due to these propertiesand the finer structureand lead distribution a superior bearing issecured.

Preferably, but not necessarily, and without limitation thereto, thecopper is in the form of a copper-base alloy containing silicon, siliconacting to secure an excellent dispersion of the lead through the metalof the built up part. Such an alloy may consist of 2 to 4.7% silicon, atleast 0.1% tin throughout this range of silicon, with the balanceapproximately all copper. The maximum amount of tin for any value ofsilicon up to 3% may be as high as 2% and should not exceed this value,While when the silicon is of tin. Appreciable amounts up to 0.5% zinc,'

or in any event preferably not more than 1% zinc, may be incorporatedinto the alloy for improving its working qualities, and, if desired, asmall amount of phosphorus may be incorporated for improving the weldingproperties of the rod. Appreciable results will be obtained with as lowas 0.005% phosporus, and preferably the phosphorus should not exceed0.1% with the higher amounts of silicon and tin and 0.25% with the loweramounts of silicon and tin, lest it render the metal fhot short. Asatisfactory specific example of this metal is silicon 3.5%, tin 0.5%,balance copper, and, if desired, either or both 0.05% phosphorus and0.25% zinc substituted for part of the copper. Such metal has greatductility and high strength. It works free ly both hot and cold, and hasexcellent resistance to corrosion. It also machines freely, and presentsa good bearing surface.

If desired, the copper-base alloy may consist of binary silicon-bronze,with or without small amounts of zinc or phosphorus, or both, within theranges of zinc and phosphorus above specified. The binary alloys withthe addition of small amounts of manganese may also be employed. From0.5 to 1.25% manganese will give satisfactory results. Bronzes of thisgroup may above approximately 3% the maximum amount 7 contain tosilicon, about 3 to 3.5% being the preferred amount. If the alloys arecast the phosphorus may be as high as ther ccppenbase alloys as, forexample, br sy tin b-ronzes may be employed. Preferably the amount oftin is about 10%, but lower values, say down to 1%, and higher values,say to 12%, will give fairly satisfactory results. .osphorus also beadded to these alloys, erably not more than 6.05%. However, if red, thephosphorus may run up to 1%. an is ample of a suitable alloy of thisgroup is 10% i 12% phosphorus, balance copper.

ary copper-phosphorus welding rod may also e employed for thecopper-base alloy as; for example, copper rods containing 6 to l@% phos-The tin be omitted, if desired, from the hereinbeziore described alloysof which the body of the rod is formed, and may be placed in the coatingof the rod, as above described, so that the will alloy with thecopper-base when the rod is melted.

if desired the alloy of which the welding rod is 25v made may containnickel as the equivalent of silicon in respect to improving thedispersion of the lead. Up to 1% nickel will be sufiicient to disperseup to about 10% lead, and proportionate amounts of nickel may beemployed for higher amounts of lead. In general, any or" the abovementioned alloys which do not contain silicon may have incorporatedtherein a small amount of nickel for this purpose. As little as 0.1%nickel will give appreciable results, but preferably about 1% thereof isemployed as giving satisfactory results for all values of lead. It willbe understood by those skilled in the art that the term welding rod isused herein in its ordinary sense as implying a rod, pencil, wire,ribbon and the like of convenient size for use in electric arc welding.

It will be understood that within the scope of the appended claims widedeviations may be made from the above described welding rods andcopper-content alloys without departing from the spirit of theinvention.

I claim:

1. The method of forming a leaded cupreous metal mass which comprisesbuilding up said mass on a backing by progressively electric arcdepositing thereon the end fractions of a welding rod which ispredominantly copper and contains appreciable amounts up to lead.

2. The method of forming a bearing surface of leaded cupreous metalcomprising mechanically associating material 0! the group consisting ofcopper and copper base alloy with material of the group consisting oflead, reducible lead alloy and of leaded cupreous metal comprisingdepositing on and bonding to a metal backing, by use of an electric are,metal irom a welding rod which is predominantly copper and containsappreciable amounts up to 1.5% lead; which lead ispresent in saidwelding rod in the form of metal of the group consisting of lead and.tin-lead alloy of which latter the tin content does not exceed 12% ofthe metallic constituents of said rod the electric are being causedprogressively to melt the end fractions of said rod and project anddeposit them to build up said backing with said leaded metal. V

4. The method oi forming a bearing surface of leaded cupreous metalcomprising depositing on and bonding to a metal backing, by use of anelectric are, metal or" an elongated welding rod by causing the arcprogressively to melt the end fractions of said rod and project anddeposit them to build up the backing with said leaded metal, which rodis predominantly copper and contains tin and lead, the amount of tin notexceeding 12% and of lead not exceeding 15% of the metallic constituentsof said rod, the lead being present in the form of metal of the groupconsisting of lead and tin-lead alloy.

5. The method of forming a bearing surface of leaded cupreous metalwhich comprises depositing on and bonding to a metallic backing, by useof an electric arc, metal from an elongated metallic welding rodcomprising a leaded cupreous metal mass which is predominantly copperand contains 0.1 to 12% tin and appreciable amounts up to 15% lead, bycausing the arc progressively to melt the end fractions of said rod andproject and deposit them to build up said backing with the metal of saidbearing surface.

6. The method according to claim 5 in which the leaded cupreous metalmass comprised by said rod also contains 0.01 to about 4.7% silicon andnot more than about 2% tin.

'7. The method of forming a bearing surface comprising depositing on abacking member by the electric are a leaded cupreous metal from awelding rod containing approximately copper 89%, tin 9%, and lead 2%.

IRVING T. BENNETT.

Patent No. 2,166,700.

CERTIFICATE OF CORRECTION.

y 8, 959- IRVING T. BENNETT.

It is hereby certified that error appearsv in the printed specificationof the above numbered patent requiring correction as follows: Page 1,second colunm, line 10, for the word "casing" read casting; and that thesaid Letters Patent should be read with this correction therein that thesame may conform to the record of the case in the Patent Office Signedand sealed this 5th day of September, A. D. 1959.

Henry Van Arsdale,

(Seal) Acting Commissioner of Patents.

